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Inter-University Consortium for Political and Social Research (ICPSR): Codebooks

Data resource covering such topics as population, economics, education, health, social and political behavior/attitudes, terrorism, history, crime, aging, and substance abuse.


A codebook provides information on the structure, contents, and layout of a data file. Look at the codebook of a study before downloading the data files.

While codebooks vary widely in quality and amount of information given, a typical codebook includes:

  • Column locations and widths for each variable
  • Definitions of different record types
  • Response codes for each variable
  • Codes used to indicate nonresponse and missing data
  • Exact questions and skip patterns used in a survey
  • Other indications of the content and characteristics of each variable

Additionally, codebooks may also contain:

  • Frequencies of response
  • Survey objectives
  • Concept definitions
  • A description of the survey design and methodology
  • A copy of the survey questionnaire (if applicable)
  • Information on data collection, data processing, and data quality

See a sample code book.

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